This invention relates generally to the field of pallets, relatively planar support members used as a platform to allow movement of heavy and/or multiple items by a fork lift or hand truck having tines or forks insertable into or under the pallet, and in particular relates to pallets which have single deck members supported by a plural number of depending leg members. Even more particularly, the invention relates to such pallets which are nestable in a manner which minimizes the vertical height of a stack of unloaded pallets.
Pallets are well known devices commonly used in the transportation and storage of goods. A pallet has a substantially horizontal support surface, called a deck member, onto which items are placed which cannot easily be moved, either because of the size, weight and configuration of the objects themselves, or because a method is desired for easy movement of large numbers of smaller items, such as for example a number of small boxes or cartons. The pallet is configured to allow insertion of the tines or forks of a hand truck or fork lift beneath the deck member between the legs. To move the pallet the tines are inserted beneath the deck member and the tines and the pallet are raised off the floor, the fork lift or hand truck having power means sufficient to raise the loaded weight of the pallet, typically accomplished by hydraulic mechanisms. The fork lift or hand truck being wheeled, the loaded pallet can then be moved to the desired location, such as onto or from a transport trailer or to a different location within a warehouse. The pallet is then lowered to the ground and the tines are withdrawn. Common pallets are constructed with an upper deck member and a lower deck member separated by brace members, and the tines are inserted into the vertical gap between the two deck members and laterally between the brace members. Because the deck members must be separated a distance of several inches to provide the gap for the tines, and because the lower deck member of a superior pallet rests directly on the upper deck member of an inferior pallet when stacked vertically, storage and transport costs for unloaded pallets are increased, since the pallets are not vertically nestable.
To reduce the vertical height of unloaded pallets when stacked, i.e., to increase the number of unloaded pallets which can be stacked in a given vertical space, nestable pallets having single rather than double deck members have been developed. The single deck member is the planar support member for the goods and is supported by a plural number of leg members which are positioned to allow insertion of the fork lift tines beneath the deck member between adjacent legs. The leg members have open interiors and tops, and are mounted onto the deck member such that the open interior is exposed from or accessible through the upper side of the deck member. The outer configuration of the legs taper downward, such that the legs of a pallet placed directly on top of another similar pallet will enter the open interiors of the legs in the lower pallet, rather than sit atop the deck member of the lower pallet, thus reducing the vertical distance between the deck members. This allows a much larger number of unloaded pallets to be stacked in a given space.
To achieve the maximum density of nested pallets, the pallets would ideally be designed such that the lower surface of the deck member of a superior pallet contacts the upper surface of the deck member of the immediately inferior pallet. In other the words, the legs members are designed such that they are fully insertable into the interior spaces of the legs in the lower pallet such that no gap exists between the deck members of adjacent pallets. While this construction maximizes nestability of the pallets, it presents a problem in that it is difficult to separate the tightly nested individual pallets for use, usually requiring the pallets to be separated manually. This reduces work efficiency, as ideally the pallets should be separable by the fork lift operator using only the tines of the fork lift.
An early design which addresses this problem is shown in U.S. Pat. No. 3,641,949 to Monk. Monk discloses a nestable single deck member pallet which can be more densely stacked with the pallets oriented in one direction, but which provides a less dense stack if alternating pallets are oriented in a different direction, thus providing a larger separation between adjacent deck members so that the tines can be easily inserted therebetween. This construction, however, still requires that the pallets be manually separated when nested in the dense orientation, and does not provide a nested stack of maximum density which is still accessible to the fork lift tines. A different approach is taken in U.S. Pat. No. 4,879,956 to Shuert, wherein the pallet is constructed to allow access for the fork lift tines when the pallets are nested in a manner to provide maximum density. As shown in FIG. 10 of that patent, the pallets are provided with short upper and lower ramp surfaces which in combination with the ramp surfaces of an adjacent stacked pallet define a notch to receive the tips of the fork lift tines. This design requires the deck member to be relatively thick if formed of wood, since the ramps must be cut into both the upper and lower surface of the deck member, or requires it be formed of plastic in the generally complicated manner disclosed in that patent. This precludes usage of this construction in composite pallets formed of two planar sheet members joined by lightweight filler material, such as corrugated cardboard positioned between two thin plywood sheets. Another drawback to this design is that the notches are vertically aligned in columns when pallets are stacked, meaning that there is very minimal separation between the notches of adjacent pallets. With the added problem that there is little visual demarcation between adjacent notches, the likelihood of a fork lift operator being able to quickly and easily separate a single pallet from a stack using the tines of the fork lift is very low, and will typically require several attempts to set the tips of the tines at the exact proper height to meet the desired notches.
It is an object of this invention to provide a construction for nestable single deck pallets which allows vertical stacking in a manner of maximum density, where individual pallets can be removed from the nested stack using only the tines of a fork lift, without the need to manually separate or remove the individual pallet. It is a further object to provide such pallets where the separation is accomplished by providing a pair of cut-outs or notches on one or more sides of the deck member, the notches located asymmetrically on each side relative to the midpoint of the side, thereby allowing the pallets to be stacked such that the notches of adjacent pallets are not vertically aligned in a single column in order to increase the visual demarcation between adjacent notches. It is a further object to provide such notches in pallets having deck members constructed of composite materials, whereby the deck member is formed with two thin, planar sheet members connected by relatively lightweight internal material, such as corrugated cardboard.